This invention relates to a device for holding a dial indicator and for permitting adjustment of the dial indicator relative to a supporting member.
The dial indicator is a long known and widely used instrument employed by machinists for a wide variety of purposes. A dial indicator is used extensively to locate the position of workpieces in machine tools. For example, when workpieces are chucked in lathes or in boring, drilling or milling machines, it is necessary to center the workpiece accurately with respect to the spindle and cutter of the machine. Also, it is commonly necessary to locate the positions of openings, or of walls or flanges, etc. and as well as heights of various objects of machine work.
The dial indicator is a form of instrument having a graduated dial and having a hand which is connected to a contact point or feeler by a system of multiplying levers so that a very slight movement of the feeler is greatly magnified by the indicating hand. The feeler is placed in contact with the part to be tested, and variations, either in size, alignment, or concentricity, depending upon how the indicator is used, are shown by the movement of the hand relative to the dial, which is graduated to read thousandths or ten thousandths of an inch.
Such an instrument must be delicately handled to avoid damage to it and also to permit it to record accurate readings. Accordingly, the indicator must be held firmly and in a steady position relative to the work in order to avoid false deflections of the indicating hand. Its initial setting relative to the work must be made gently in order to avoid any forceful or sharp engagement of the feeler with the work. A further requirement is that the initial setting of the indicator should be effected precisely but easily so as to enable an accurate reading to be obtained while conserving valuable work time.
Prior arrangements for mounting and permitting adjustment of dial indicators either are complex, expensive or cumbersome to use or are incapable of effecting very fine and precise adjustment of the indicator in an easy manner.